PE21.1-5 | Rheumatology — Practice Quiz

Correct. Henoch-Schönlein Purpura (IgA vasculitis) is caused by IgA1-dominant immune complex deposition in small vessels (skin, gut, joints, kidney), triggering leukocytoclastic vasculitis. The mandatory palpable purpura without thrombocytopenia is the hallmark.

HSP (IgA vasculitis) is the commonest systemic vasculitis in children. The mandatory criterion is palpable purpura in a dependent/buttock distribution; renal involvement (HSP nephritis) requires EULAR/PRINTO/PRES monitoring for at least 6 months.

IgM complexes are not characteristic of HSP. Anti-dsDNA is the marker for lupus nephritis. Platelet consumption describes immune thrombocytopenia. HSP is defined by IgA-dominant deposits on immunofluorescence.

Correct. The most feared complication of Kawasaki Disease is coronary artery aneurysm (CAA), occurring in up to 25% of untreated cases. Echocardiography is mandatory at diagnosis, at 2 weeks, and at 6–8 weeks to detect and monitor CAA.

Kawasaki Disease requires echocardiography at diagnosis to screen for coronary artery aneurysm. IVIG 2 g/kg as a single infusion within 10 days of fever onset, combined with aspirin, is the cornerstone treatment to prevent this complication.

Renal involvement is not a primary feature of Kawasaki. Arthritis occurs but is not the critical complication. Hepatic vein thrombosis is not associated with Kawasaki. Coronary aneurysm is the defining serious complication that dictates urgent treatment.

Correct. Anti-Smith (anti-Sm) antibody is highly specific for SLE (specificity >95%), though sensitivity is only 25–30%. It is included in both SLICC 2012 and EULAR/ACR 2019 classification criteria for SLE.

The SLE antibody triad to remember: ANA (most sensitive, low specificity), anti-dsDNA (high specificity + correlates with nephritis activity), anti-Sm (highest specificity). SLICC 2012 and EULAR/ACR 2019 are the current classification systems for paediatric SLE.

Anti-Ro is seen in SLE but also in Sjögren's syndrome and neonatal lupus — less specific. Anti-histone is typical of drug-induced lupus. Anti-SCL-70 (anti-topoisomerase I) is the marker for diffuse systemic sclerosis, not SLE.

Correct. Oligoarticular JIA (≤4 joints affected in the first 6 months) is the commonest subtype in children, particularly in young girls with positive ANA. Despite the absence of clinical uveitis now, this subtype carries the highest risk of chronic anterior uveitis (10–20%), mandating regular slit-lamp screening.

Oligoarticular JIA (≤4 joints in first 6 months) is the commonest JIA subtype (ILAR classification). ANA-positive young girls have the highest uveitis risk and need regular ophthalmology follow-up every 3 months, even without symptoms.

Systemic JIA (Still's) requires quotidian fever plus rash plus serositis/organomegaly. Polyarticular RF-positive resembles adult RA (≥5 joints, older girls). Psoriatic JIA needs psoriasis or first-degree relative with psoriasis. The clinical picture fits oligoarticular JIA.

Correct. A Z-score of +2.5 to +5.0 indicates a small coronary aneurysm (internal diameter <5 mm). Management is continued low-dose aspirin (3–5 mg/kg/day) until the aneurysm resolves. Larger aneurysms (Z-score ≥10 or diameter ≥8 mm) are classified as giant aneurysms requiring anticoagulation.

Kawasaki coronary aneurysm severity classification by Z-score: small (2.5–5.0), medium (5.0–10), giant (≥10 or ≥8 mm absolute). Low-dose aspirin is the mainstay for small aneurysms; anticoagulation is added for larger ones.

A Z-score >2.5 is abnormal. Giant aneurysms are Z-score ≥10 or diameter ≥8 mm — this case does not qualify. LMWH bridging is used for larger aneurysms. Low-dose aspirin is appropriate for small aneurysms.

Correct. Class IV (diffuse proliferative) lupus nephritis is the most severe form. 'Wire-loop' lesions on light microscopy and subendothelial immune deposits on electron microscopy are hallmarks. It affects >50% of glomeruli and requires aggressive immunosuppression (mycophenolate mofetil or cyclophosphamide induction).

ISN/RPS lupus nephritis classification: Class IV (diffuse) is the most severe, characterised by wire-loop lesions, low C3/C4, and nephritic-nephrotic overlap. Induction with MMF or pulse cyclophosphamide + steroids is standard; hydroxychloroquine is added to all lupus nephritis regardless of class.

Class II is mesangial disease (mild). Class III (focal) affects <50% of glomeruli. Class V is membranous with predominantly subepithelial deposits — the membranous 'spike-and-dome' pattern, not wire-loops. Wire-loops are Class IV.

Correct. Systemic JIA (sJIA/Still's disease) is characterised by quotidian (once-daily spiking) fever ≥2 weeks, the classic evanescent salmon-pink rash, arthritis, lymphadenopathy, and hepatosplenomegaly. Markedly elevated ferritin (often >10,000 ng/mL) is a key biomarker and raises concern for macrophage activation syndrome (MAS).

Systemic JIA (ILAR classification) carries the highest mortality risk among JIA subtypes due to macrophage activation syndrome (MAS — ferritin >10,000 + cytopenias + coagulopathy). IL-1 and IL-6 inhibitors (anakinra, tocilizumab) are now first-line biologics for sJIA.

Oligoarticular JIA has ≤4 joints, no systemic features. Reactive arthritis follows infection and lacks the daily fever pattern/rash. Kawasaki presents with fever ≤2 weeks + mucocutaneous features without this rash pattern. The combination of quotidian fever + evanescent rash + very high ferritin = sJIA.

Correct. Per EULAR/PRINTO/PRES guidelines, all children with HSP should have urinalysis (and blood pressure monitoring) performed at every visit for at least 6 months after diagnosis, as nephritis can present or worsen weeks after the initial episode. Late nephritis is the main long-term concern.

HSP nephritis (IgA vasculitis nephritis) determines long-term prognosis. EULAR/PRINTO/PRES 2010 criteria mandate urinalysis (proteinuria + haematuria) and BP monitoring at every visit for at least 6 months. Severe nephritis (ISKDC Grade III–V) requires immunosuppression.

HSP nephritis can develop or worsen weeks after the purpura resolves — stopping monitoring at 1–2 weeks misses late presentations. 1-month monitoring is insufficient. Waiting for hypertension before monitoring delays detection of early nephritis, which is silent.

Correct. For polyarticular JIA with inadequate response to methotrexate (the standard DMARD), adding a TNF-α inhibitor such as etanercept is the evidence-based next step per ACR/EULAR/IAP guidelines. Anti-TNF biologics (etanercept, adalimumab) are the established first biologic choice for polyarticular JIA.

JIA treatment ladder: NSAIDs (symptom relief) → methotrexate (first-line DMARD; 10–15 mg/m²/week) → anti-TNF biologics (etanercept or adalimumab) for MTX-inadequate disease. Intra-articular corticosteroid injections are used for oligoarticular disease. IL-6 inhibitor (tocilizumab) is licensed for polyarticular and systemic JIA.

Long-term oral corticosteroids as monotherapy cause significant growth suppression and are not a disease-modifying strategy in JIA. Hydroxychloroquine has minimal efficacy for polyarticular JIA. Azathioprine is not a standard DMARD for JIA — methotrexate failure triggers a biologic step-up.

Correct. The classic Kawasaki criteria require fever ≥5 days plus ≥4 of 5 CREAM features: Conjunctivitis, Rash, Enanthem (lips/oral), Adenopathy (cervical ≥1.5 cm unilateral), Mucous membrane/extremity changes. The vignette documents fever, bilateral conjunctivitis, cracked lips, extremity changes, and rash — but cervical lymphadenopathy is not mentioned. Of the 5 CREAM features, lymphadenopathy is the least common (~50%) and is absent here.

Kawasaki CREAM criteria: Conjunctivitis (bilateral non-purulent), Rash (polymorphous), Enanthem (lip/oral changes), Adenopathy (cervical ≥1.5 cm), Mucous-membrane/extremity changes. Fever ≥5 days + ≥4 CREAM features = classic Kawasaki; ≥5 days fever + <4 CREAM + coronary changes = incomplete Kawasaki (echo required).

Fever ≥5 days is present (2 weeks). Rash is present. Lip/oral changes (cracked lips, strawberry tongue) are present. Extremity changes (indurated oedema of hands) are present. The missing criterion is cervical lymphadenopathy.